Technical Field
The present disclosure relates to an organic light emitting display device and a method of manufacturing the same. More particularly, the present disclosure relates to an organic light emitting display device to improve optical efficiency and prevent deterioration in reliability of thin film transistors, and a method of manufacturing the same.
Description of the Related Art
Image display devices for displaying a variety of information on a screen are significant technologies in the information-technology era and are being developed into slimmer, lighter weight, more portable and higher-functional forms. In response to these requirements, organic light emitting diodes that display an image by controlling the amount of light emitted by an organic light emitting layer attract a great deal of attention as flat panel display devices capable of reducing weight and volume, which are drawbacks of cathode ray tubes. Organic light emitting diodes (OLEDs), which spontaneously emit light, have low power consumption, rapid response speed, high luminous efficacy, high brightness and wide viewing angle.
Organic light emitting diodes include a light emitting element and a pixel circuit which independently operates the light emitting element and includes a plurality of transistors.
Here, when light generated in the light emitting element travels toward a substrate, total reflection occurs in an inner area between the light emitting element and the substrate due to the difference in refractive index between thin films disposed between the light emitting element and the substrate. Accordingly, the light extraction efficiency of light emitted to the rear surface of the substrate is lowered to 20 to 35%. In addition, a part of light generated in the light emitting element travels toward a non-light emitting area, rather than a light emitting area, thus causing deterioration in light extraction efficiency. In addition, when light scattered by total reflection which occurs inside the substrate is incident upon the channel of a thin film transistor included in a pixel circuit, it is difficult to control on/off of the thin film transistor due to photon energy, thus disadvantageously causing deterioration in reliability of the thin film transistor.